After being hounded for months about how it plans to make money, Twitter (finally) is set to provide an answer, likely at the company's Chirp conference in mid-April. What'll it be?

The consensus is that an ad platform of some sort will be announced. But by our count, over the past 18 months or so, Twitter executives and investors have mentioned no fewer than five different possible sources of revenue. Here, in anticipation of the unveiling next month, is what Twitter has said about each, and which of those aspirations they've actually done something about.

Advertising

What they said: Twitter has said as far back as November 2008 that it would consider adding ads to search-result pages. More recently, though, executives have said that "traditional web banner advertising isn't interesting to us," and instead have said the ad model they will reveal will be "fascinating," "non-traditional," "really cool" and "amazing." So specific! As of February, it was in the "test phase."

What they've done: Nothing – although head of product management and monetization Anamitra Banerji said in late February that the ad platform would likely launch in the next month or so.

E-commerce

What they said: Twitter board observer Todd Chaffee said in June that the company was considering e-commerce as a revenue stream. Since people are using Twitter to get product recommendations, he said, it would only make sense that people would be able to buy products via the site too.

What they've done: Nothing.

Premium accounts

What they said: Twitter co-founder Biz Stone said in August that the company would charge users for "premium accounts". In November, Stone said the plans were well on their way and that a pay-for-package offering that would include verified streams and analytics would launch by the end of the year.

What they've done: The company has not started charging for premium accounts. However, it has rolled out free business-friendly features like "contributors," which helps differentiate between multiple users of a single Twitter account.

Mobile deals

What they said: At our own EconSM conference, Kevin Thau, Twitter's director of mobile business development, said the company would make money from handset deals and also by getting some sort of cut of the carriers' data business.

What they've done: Twitter has dozens of relationships with carriers—financial details of which are unknown. The company did, however, link up with Peek in November to launch a $99 device designed for the frequent Tweeter.

Search

What they said: Thau also said at our conference that Twitter would monetise search "in some way".

What they've done: Twitter has since licensed its stream of Tweets to Microsoft, Google and Yahoo – which are all using the data to add real-time results from Twitter to their search engines. The Microsoft and Google deals alone are believed to be worth as much as $25m.